Biodegradable composition

ABSTRACT

A biodegradable composition, is obtained by heating a melting together at least one lignin and/or a lignin containing material with a protein. This composition may contain one or more additives. Also disclosed are articles produced with this composition.

BIODEGRADABLE COMPOSITION

The present invention refers to a biodegradable composition, whichcontains a lignin and/or a lignin-containing material and a protein,said composition being useful for the production of biodegradable shapedarticles, for example throw-away articles, advertising articles, labels,cups, flower-pots, reels of thread, candle-cups, and the like as well asfilms, or foamed articles. The invention also refers to the articles,which are made from a material according to the present invention.

Lignin is a biodegradable raw material which is found abundant innature. Lignin is a cell-wall material of wood, straw, and likematerials and is obtained as a side-product when these materials areprocessed, especially in the production of wood-cellulose, which is thestarting material for the paper industry. On the basis of the differentprocesses used to isolate lignin, and the different types of ligninobtained therewith, lignin is named mainly as sulphate-lignin, orKraft-lignin, sulphonate-lignin, organosolv-lignin which is obtained byextraction with organic solvents, like ethanol, or n-butanol, ligninwhich has been obtained by treatment with water vapour, oracid-hydrolysed lignin. The different processes to produce these ligninsare the lignins obtained therewith have been described in theliterature. All these lignins may be used for production of thecompositions as defined herein later on.

For the use according to the present invention the lignin need not berelatively pure and isolated. It suffices to use directly a lignincontaining material. It is possible to use wood or another lignincontaining material directly, as a natural renewable raw-material, inplace of isolated lignin. In sawmills wood is obtained in the form ofsawdust in different sizes. Often boughs, branches of trees or bushesare treated in a shredder to produce small pieces. These materials maybe used directly to produce shaped articles. In this sense, the presentinvention refers also to use of lignin containing materials, preferablyin the form of small or fine particles, preferably in the form of smallparticles, optionally together with separately produced relatively purelignin, to produce shaped articles which are dimensionally stable, yetbiodegrade in nature. Proteins, lignins and lignin containing materialsare well compatible and adhere well with each other chemically orphysically when used according to the present invention. This yieldsgood products which may be produced easily and are reproducible.

Articles made from biodegradable materials are known. The biodegradablematerials according to the present invention are, compared with knownmaterials, cheap and simply to make, for example in melt-processing bycompression-molding by extrusion, or by injection molding. This dependson the selected composition. Products are obtained with very goodproperties having a high stability against humidity so that the physicalproperties remain stable within a large humidity range. Articles madetherefrom have a natural color and according to the chosen compositionfor example also the natural color of wood which is very attractive.Compositions according to the present invention containing lignin, aprotein and optionally a flame retardant have excellentself-extinguishing properties. The have an excellent price/performanceratio, which is an important factor for the commercial success.

The present invention is defined in the claims. The present inventionespecially refers to a biodegradable composition, which is characterizedin that said composition has been obtained by heating and meltingtogether at least one lignin and/or a lignin containing material with aprotein, and that said composition optionally contains one or moreadditives, whereby said additives are selected from the group ofmodifying agents, alkenol polymers, fillers, lubricants, plasticizers,thermoplastic polymers, stabilizers, flame retardants, dyestuffs,nucleating agents, foaming agents, pigments and mixtures thereof. Theweight ratio of the dry lignin and/or the dry lignin containing materialon the one side to the dry protein on the other side in said compositionis preferably from 99.95:0.05 to 20:80, preferably from 99.95:0.05 to40:60, preferably from 98:2 to 60:40, and preferably from 97:3 to 75:25.

the present invention further refers to a starting composition which onheating and melting yields a composition according to the presentinvention, which is characterized in that said starting compositioncontains the following components: (i) a lignin and/or a lignincontaining material; (ii) a protein which optionally has beendeprotonated and (iii) optionally one or more additives which areselected from the group comprising of modifying agents, alkenolpolymers, fillers, lubricants, plasticizers, thermoplastic polymers,stabilizers, flame retardants, dyestuffs, nucleating agents, foamingagents, pigments and mixtures thereof, wherein the weight ratio of thedry lignin and/or the dry lignin containing material on the one side tothe dry protein on the other side in said composition preferably is form99.95:0.05 to 20:80, preferably from 99.95:0.05 to 40:60, preferablyfrom 98:2 to 60:40, and preferably from 97:3 to 75:25.

The composition may, depending on the chosen composition, by present inthe form of a powdery mixture, a spray dried powder, a melt or a shapedarticle made thereof.

it is to be assumed that the lignin and the protein associate or bindtogether so that after heating a lignin/protein reaction product isobtained. This especially is the case, if a deprotonated protein is usedas described further on. If a lignin containing material is used, forexample wood, which is further in this text used as an expressionincluding also other lignin containing materials, it may also be assumedthat on heating, the protein associates with or binds itself to thereactive groups of the lignin which is contained in the wood. This mayespecially be assumed if deprotonated gelatine is used. On the basis ofthe increase of the viscosity of the mixture while processing it appearsthat a cross-linking reaction takes place. However, this explanationshall not limit the present invention.

If for example lignin and gelatine or deprotonated gelatine is mixed ina kneader at elevated temperature, a homogenous melt is formedinitially, whereby on continued processing the viscosity of thecomposition increases. By cooling the composition it is possible to stopthis increase resp. the cross-linking. By this it is possible to workwith a two or multi-step process and initially produce a compositionwhich is not cross-linked or only cross-linked to a low degree which ina further step is worked into the finished article. If the usedgranulate consists mostly of lignin and a protein then preferably aheated press is used for producing shaped articles as by the continuingcross linking and increasing viscosity an extruder or an injectionmoulding machine could be blocked. The selection of the apparatus toproduce of the shaped article depends of the type of composition andpresents no problem to the expert.

In order to produce the composition of the present invention it isconvenient to mix the lignin and/or the lignin containing material withthe protein, optionally under heating and subsequently adding theadditives. It is also possible to mix the additives together with thelignin and/or the lignin containing material and heating the mixture.Preferably a granulate is produced initially, wherein the lignin and/orthe lignin containing material is not crosslinked or pre-crosslinkedwith the protein. The granulate may then be mixed with further additivesand processed to a shaped article applying heat.

If wood is used in the mixture it is possible to impregnate the woodwith the protein and optionally with the lignin and further additives sothat a granulate is obtained which can be processed under heat to yielda shaped article. Preferably the impregnated product is made from a woodcontaining of small particles. Such a wood is for example sawdust, as isobtained by sawing wood. Wood in small particles is also obtained bychipping or shredding wood for examples as wood shavings.

The weight ratio of the dry lignin containing material to the dryprotein is preferably the same as mentioned above for the ratio oflignin to the protein. It is however possible to chose other weightratios, for example a weight ratio of from 99.95:0.05 to 70:30,preferably 98:2 to 80:20, or 97:3 to 90.5:9.5.

The lignin component of the composition may be lignin only or a mixtureof lignin and lignin containing material or a lignin containing materialalone, depending of the type of article to be produced, its use andcolor and other properties and the processing method to be applied. Theratio of the components in the mixture depends mainly on the productproperties of the final product. An important function are the degree ofthe cross-linking and the additives. By adding plasticisers and otheradditives, especially thermoplastic polymers, as described further on,the properties of the described compositions may be optimised and notrepresent a problem to the expert in the art.

As lignin all the lignins may be used for example lignin made from woodof fir-wood, spruce, oak-tree, aspen, pine-tree or from straw or similarmaterials and is present in the form of sulfate-lignin or Kraft-lignin,sulphonate-lignin, organosolv-lignin, lignin which has been treatedunder vapor pressure and acid-treated lignin. Lignins which contain nosulphur are preferred. These also have together with lignin somewhatdifferent properties. Depending on the required properties of thefinished product, especially with reference to the mechanicalproperties. the water-resistance resp. water-solubility or color, it ispossible that a sulphur containing lignin is preferred. Same types oflignin may have different properties depending on their origin. This isa problem of optimisation. All types of wood as well as other lignincontaining materials may be equally used to produce the compositionaccording to this invention. Preferred is wood.

The expression “lignin” as used herein comprises chemically modifiedlignin, for example alkoxylated lignin, such as ethoxylated orpropoxylated lignin, which has been obtained by treating lignin withethylene oxide or propylene oxide in an alkaline medium. Such ligninderivatives are known.

The protein as used according to this invention is preferably avegetable or a animal protein an known per se, such as collagen,gelatine or case in, however, all proteins which are commerciallyavailable may be used. The expression “protein” includes also chemicallymodified, i.e. derivatives of proteins, for example proteins modifiedwith acrylic acid or methacrylic acid or with glycidyl methacrylate,where from said derivatives of gelatine are preferred. These may becross-linked by electron- or UV-light. Such derivatised proteins areknown. The used protein preferably contains about 5% by weight of water,calculated to the weight of the dry protein, preferably about 6% byweight to 20% by weight water or more, preferably 8% by weight to 18% byweight. It is also possible to use proteins with less than 5% by weightof water resp. proteins which are essentially free of water. Preferredare gelatine and derivatives of gelatine.

Lignin and and/or lignin containing materials may be processed withproteins in different ways, as described above, to yield thecompositions according to the present invention. The melting together ofthe components can be realised within a wide temperature range, i.e.from about 80° C. to about 260° C. Preferred is a range from 100° C. to200° C., preferably from 100° C. to 170° C. and preferably from about120° C. to 165° C., optionally together with the additives as namedherein. The softening point resp. the melting point of lignin depends onthe molecular weight and the production method of the lignin and is atabout 80° C. to about 145° C. Lignin mixed with protein may be processedat temperatures within the range of 80° C. to 100° C. The components maybe molten together in a mixer or kneader at the mentioned temperatureswhereby preferably a granulate is produced. It is also possible to meltthe components in an extruder and subsequently granulate the melt,whereby process conditions and composition are to chosen such that theextruder is not blocked.

A special embodiment of the present invention is that a deprotonatedprotein is used, i.e. a protein which has been deprotonated at elevatedacid value (p_(H)). Proteins are polypeptides which contain carboxylgroups as well as amino groups as side chains in the same molecule.Proteins therefore are amphoteric and have an isoelectric point at whichthe number of negative charges and the number of positive chargespresent in the same molecule are equal. Gelatine for example, dependingon the method of its production, has its isoelectric point at the acidvalue (p_(H)) of about p_(H) 4.7 to p_(H) 5.0. The acid groups presentin gelatine molecule are neutralised at about p_(H) 1.5 to p_(H) 6.5,whilst the different kinds of amino groups are deprotonated in the rangeof p_(H) 8 to p_(H) 11.5. This means that at p_(H) 6.5 practically allcarboxyl groups are being neutralised. Deprotonation of certain aminogroups starts at p_(H) 8 whereby all the amino groups are beingdeprotonated at p_(H) 11.5. Deprotonated polypeptide contain free andreactive electrons which are able to associate and to react with lignin.The higher the degree of deprotonation the stronger will be the reactionof the protein with the lignin thereby modifying the lignin. The ratioof the components within the composition of the lignin/protein reactionproduct may be optimised according to the required properties of thefinal product such as mechanical properties, water resistance or color.The protein used in the composition has preferably been deprotonated atleast at p_(H) 8, preferably at p_(H) 10 and preferably at p_(H) 11.5whereby at p_(H) 11.5 the protein will be completely deprotonated. Thedeprotonated protein is, with reference to carboxyl group contained inthe protein, preferably a alkali- or earth alkali salt, preferably asodium or potassium salt. It is obtained by treating the protein withthe respective alkali or earth alkali salt in a n aqueous medium, forexample with sodium hydroxide or potassium hydroxide or the respectivecarbonates or bicarbonates. The preferred weight ratio of the dry ligninand/or lignin containing material on the one side to the deprotonatedlignin (calculated to the dry substance) on the other side have beenindicated above. Weight ratios of form 97:3 to 88:15 and from 97:390.5:9.5 may also be used.

The present invention therefore refers also a biodegradable composition,which is characterized in that said composition is obtained by heatingand melting together of at least one lignin and/or lignin containingmaterial with a deprotonated protein, and that said compositionoptionally contains one or more of the additives as mentioned above.

For producing the composition containing deprotonated protein, theanalogous procedure is used as described above for compositionscontaining non-deprotonated protein. The deprotonated protein is mixedwith the lignin or the lignin containing material whereby the optionaladditives are added immediately or subsequently. The mixture is thenmolten to a uniform mixture and optionally granulated. This can be madedepending on the selected composition for example in kneader, mixer orextruder. The deprotonated protein may also be produced in situ duringthe mixing process resp. melting process by adding to the startingmixture which contains non-deprotonated protein, dry or aqueous alkalihydroxide, earth alkali hydroxide, alkali carbonate or earth alkalicarbonate. Any excess of alkali in the reaction product is preferablyneutralised for example by the addition of lignin or a lignin containingmaterial, for example wood or by adding a polybasic acid, for exampletartaric acid or citric acid. The acid value (p_(H)) of the compositionproduced in this manner is preferably neutral and is preferably withinthe range of 6.5 to 7.5.

It is possible to dissolve the protein as well as the lignin at higheracid value in water and adding the optional additives and subsequentlyprocessing the mixture obtained. By using this method a more intensivereaction of the components is obtained.

Cross-linking the lignin component with the protein component has theeffect that the composition is hardened. In this manner preferably anon-cross-linked or partially cross-linked mixture resp. a non hardenedor a partially hardened mixture is produced initially preferably in theform of a granulate, which in a further step is processed to yield thefinal cross-linked resp. hardened product. It is possible to produce ina first step an aqueous starting mixture containing the startingmaterials in a dissolved, dispersed and/or emulsified form, subsequentlydrying this mixture, preferably by spay-drying, whereby a dry resp.spray-dried granulate is obtained. This granulate may in a further stepbe cross-linked to yield a finished article. If this starting mixturecontains a filler, such as cellulose fibres and/or a lignin containingmaterial, such as wood, preferably sawdust, then an impregnation productis obtained, preferably an impregnated wood, preferably spray driedsawdust which can be further formed to shaped articles. The presentinvention therefore refers to a method of producing an impregnatedgranulate, said granulate being preferably spray-dried, which ischaracterized, that in a first step (i) an aqueous starting mixture ismade, in which the staring materials are present in a dissolved,dispersed and/or emulsified form whereby said starting mixturepreferably contains a filler and/or a lignin containing material,preferably wood, and that (ii) said starting mixture is dried,preferably spray-dried, so that a granulate, preferably a spray-driedgranulate, is formed wherein the lignin component and the proteincomponent are not crosslinked or only crosslinked to small degree, sothat the final cross-linking step resp. the hardening step can becarried out in a second step, i.e. when the shaped article is formed.The present invention also refers to the granulate made by said methodas well as the shaped articles made from such a granulate. By thismethod it is possible to make relatively light foam-like articles, whichbiodegrade relatively quickly.

The composition according to this invention, as obtained by heating andmelting together of at least one lignin and/or lignin containingmaterial with an optionally deprotonated protein, as described hereinabove, can be used as such and be processed into shaped articles. Thecomposition may contain additives, which are named above as component(iii). If the composition contains one or more additives, then the sumof the components by weight of the lignin component and the proteincomponent calculated to the total weight of the composition is at least20%, preferably at least 40% and preferably at least 50%, preferably atleast 60%, preferably at least 80%, calculated each time to the drysubstance.

The dry substance of all the additives named as component (iii) in thecomposition is 0.2 to 80% by weight, preferably 2 to 60% by weight,preferably 5-50% by weight or 5 to 40% by weight, calculated to thetotal weight of the composition.

The alkenol polymers as mentioned according to this invention arepartially hydrolysed polyvinyl acetates with a degree of hydrolysis offrom about 50 mol % to 100 mol %, preferably form about 65 mol % to 100mol %. These polymers are know as polyvinyl alcohols and are, dependingon their degree of hydrolysis, water-soluble. Water soluble polyvinylalcohols in their pure state are normally not thermoplastic andtherefore are processed together with known plasticisers. Preferredpolyvinyl alcohols are those with a degree of hydrolysis of 75-99 mol %,preferably 87-98 mol %, especially 75-89 mol % and 96-99 mol % and anaverage molecular weight of about 15′000 to 240′000, preferably 15′000to 180′000, preferably 40′000 to 110′000, preferably 40′000 to 80′000due to their biodegradability characteristics. The alkenol polymers aresued preferably in a concentration of from 5-40% by weight, preferably5-30% by weight, preferably 10-25% by weight, calculated to the totalweight of the composition.

Suitable filters include, for example oxides of magnesium, silicon andaluminum, chitosan, cellulose fibres, cellulose esters, celluloseethers, starch esters, starch ethers, hydroxyalkyl cellulose,hydroxyalkyl starch, ceramic powder. Wood is a lignin containingmaterial and is used as described above. If wood is used in acomparatively large excess, it is possible to consider wood also as afiller material. As such preferably wood powder, such as sawdust, isused. The fillers are present at a concentration of 3-50% by weight,preferably 5-30% by weight, preferably 5-15% by weight, based on thetotal weight of the composition.

Lubricants include for example stearates of aluminum or magnesium,lecithins and mono- and diglycerides, which are present in aconcentration of form 0.5% to 5% by weight, preferably 0.7% to 1.5% byweight.

Plasticisers include for example poly(alkylene oxides), preferablypoly(ethylene glycols) or poly(propylene glycols), ethylene glycol,propylene glycol, sorbitol, glycerol, low-molecular weight glycerins,glycerol monoacetate, diacetate, or triacetate; urea; pentaerythritol,triethyl citrate, tributyl citrate, fatty alcohols such as stearylalcohol and further known plasticisers. which are present at aconcentration of between 0.5% and 40% by weight, and more preferablybetween 0.5% and 25% by weight, preferably between 1.0% and 15% byweight or between 1.0% to 10% by weight.

Synthetic thermoplastic polymers are preferably selected form the groupconsisting of polyolefines, such as polyethylene or polypropylenes,poly(vinyl acetates) and partially hydrolysed poly(vinyl acetates) witha degree of hydrolysis of 10 mol % to 50 mol %, polystyrenes;poly(acrylic acid) esters or poly(methacrylic acid) esters,thermoplastic polycondensates, preferably polyesters, polyamides,polyester amides, poly(amide anhydride); alkylene/acrylic acidcopolymers or alkylene/methacrylic acid copolymers, preferablyethylene/acrylic acid copolymers; alkylene/maleic anhydride copolymers;alkylene/vinylalcohol copolymers. Such polymers are known. Preferredcopolymers from the group of ethylene/acrylic acid copolymers are thosewhich contain the carboxyl group partially in salt form, preferably assodium or potassium salt.

The thermoplastic polymers and copolymers as mentioned herein arepreferably water-insoluble, i.e. they dissolve less than 5% by weight,preferably less than 3% by weight, and preferably less than 2% by weightin water at room temperature (20° C.).

Preferably the composition contains these polymers and copolymers in atotal concentration of 0.2-70% by weight, preferably 0.5-50% by weight,preferably 0.5-30% by weight or 0.5-20% by weight, preferably 1-10% byweight, calculated to the total weight of the composition.

Preferred are biodegradable polymers. Preferred polyamides are knownbiodegradable polyamides, polyester amides and poly(amid anhydrides).Preferred copolymers and ethylene/acrylic acid copolymers andethylene/vinyl alcohol copolymers. Preferred biodegradable thermoplasticpolyesters are polymers derived from aliphatic hydroxy-carbonic acidswith 1 to 24 carbon atoms, which for example are made from thecorresponding hydroxy-carbonic acids or the corresponding lactones orlactides. The preparation of such polyesters is known per se. Suchpreferred thermoplastic polyesters are preferably homopolymers asderived from alpha-hydroxy-carbonic acids such as polyglycolic acids;homopolymers made from lactic acid or the corresponding lactide; or frombeta-hydroxy-carbonic acids, preferably from beta-hydroxy-propionic acidresp. beta-propiolactone or beta-hydroxy-butyric acid(poly-beta-hydroxy-butyrate); from gamma-hydroxy-carbonic acids, forexample gamma-hydroxy-butyric acid resp. from gamma-butyrolactone orfrom gamma-valerolactone; from epsilon-hydroxy carbonic acids, such as6-hydroxy-carbonic acid resp. the corresponding epsilon-caprolactonewhich yields poly-epsilon-caprolactone. Preferred are polymers made fromlactic acid, gamma-hydroxy-butyric acid, gamma-valerolactone andepsilon-caprolactone. Preferred is poly-epsilon-caprolactone.

Preferred thermoplastic copolymers are poly-hydroxy-butyrate/valerate aswell as copolymers made from hydroxy-carbonic acids as mentioned in thepreceding paragraph with aliphatic or aromatic diisocyanates, such ashexamethylene-diisocyanate. Other copolymers are known and can be usedaccording to requirements. Block-copolymers containing one of thehydroxy-carbonic acids, such as beta-hydroxybutyrate may also be used.

Homopolymers and copolymers made from hydroxy-carbonic acids have asoftening point preferably between 50° C. and 170° C., preferably at 60°C. or higher and an average molecular weight of about 40′000 or higher.

For the production of thin-walled, for example films (often calledfoils), it is preferred that the weight ratio of the lignin=proteincomponent on the one side to the homopolymer and/or copolymer on theother side within the total composition generally is 1:3 to 2:1 andpreferably 1:2 to 1:1. THE weight of the lignin/protein-component andthe polymer or polymers of the hydroxy-carbonic acids in total,especially for the production of films, in the total composition is30-90%, preferably 35-80% by weight, preferably 40-70% by weight,calculated to the dry weight of the total composition.

Preferred from the group of alkylene/vinylalcohol copolymers areethylene/polyvinyl alcohols, preferably with a molar vinyl alcoholcontent of at least 50 mol %, preferably at least 58 mol %. Mostpreferred is a vinylalcohol content between 65 mol % and 85 mol %.Alkylene/vinylalcohol copolymers are used preferably together with thementioned polyvinyl alcohols in a weight ratio of 4:1 to 1:4, preferably2:1 to 1:2. Preferred are those synthetic polymers with a softeningpoint of 260° C. or lower, preferably of 220° C. or lower, mostpreferably between 110° C. and 210° C. or lower. Polycaprolactones canbe processed at temperatures as low as 60° C., so that the lowertemperature limit of the polymers is, depending on the choice, at about60° C.

A part of the lignin within the lignin/protein component may be replacedby starch so that a lignin/starch/protein component is obtained. It isassumed that starch associates with protein in a different form thanlignin. The term “lignin/protein component” includes also thelignin/starch/protein component. The total weight of lignin and starchin the lignin/protein component corresponds to the value given above forthe lignin part within the lignin/protein component containing ligninonly. In replacing lignin partially by starch, the ratio of lignin tostarch is preferably 10:1 to 1:10, preferably 8:1 to 3:1 and preferably5:1 to 1:1.

The term “starch” as used herein comprises starches of vegetable origin,which starches are for example derived from potatoes, wheat, corn, oats,rice, and other starch containing plants. Such starch is composedprimarily of amylose and amylopectin. Potato starch regularly containsabout 30% by weight of amylose whereas certain kinds of maize forexample may contain 75% by weight of amylose or more or may consistalmost entirely of amylopectin. The compositions of the presentinvention may be produced with all starches of this kind. Preferred aremaize starch and potato starch.

The term “starch” as used herein also comprises chemically modifiedstarches, for example starch esters, preferably starch acetates,provided that the reactivity of the starch derivative is not reduced tosuch a degree that the derivative is not able any more to associate withthe protein, preferably with the deprotonated protein, which generallyis the case when the degree of substitution of the starch derivativedoes not exceed 0.05.

Modifiers are for example acid anhydrides of carbonic acids andpoly-carbonic acids such as the anhydrides of acetic acid, propionicacid, butyric acid, valeric acid, stearic acid, tartaric acid, benzoicacid, phthalic acid; epichlorohydrin, epoxy compounds, aldehydes such asformaldehyde, acetaldehyde, propioaldehyde, butyraldehyde,valeraldehyde, capronaldehyde, stearylaldehyde, crotonaldehyde,benzaldehyde, furfurol. These modifiers are capable of reacting with thelignin and/or protein and may cross-link the components, especiallyunder the influence of heat. Modifiers are also compounds which underthe influence of light, especially electron rays or UV-light, optionallyin the presence of known activators, cross-link the protein. Modifiersare used preferably in concentrations of 0.1-6% by weight, preferably2-5% by weight, calculated to the weight of the protein.

Stabilisers are for example known antioxidants, UV-absorbers orUV-quenchers or bactericides or fungicides and are used in knownquantities.

Flame retardants are known per so. They contain phosphorous, sulphur orhalogen and are present in an amount of from 0.1% to 10% by weight,preferably 1% to 6% by weight, most preferably 2% to 4% by weight basedon the total weight of the composition. The particularly preferred flameretardants are guanidinium phosphate, ammonium polyphosphate,ethylenediamine-polyphosphate (optionally in the presence of disodiumorthophosphate), guanidinium sulphate and/or ammonium sulphate. Thesecompounds are present in the composition in the amount as indicatedabove. Lignin and protein together with a small amount of flameretardant an excellent self-extinguishing composition.

The coloring agents used in the present invention are preferably knownbiodegradable colors and used in known concentrations. Nucleating agentsare for example the fillers as mentioned herein above, or magnesiumsilicate (micro-talcum) with an average particle size of about 0.1 to 5microns, and in a concentration of about 0.1% to 3% by weight,preferably 0.1% to 0.5% by weight.

Foaming agents are generally known. Examples are a combination of sodiumbicarbonate and citric acid and similar foaming agents which arecommercially available. It is also possible to add gaseous carbondioxide directly to the molten composition into the extruder barrelduring extrusion. Foamed materials often are used as packagingmaterials, in loose or in tailored form, for example for pharmaceuticalampoules. The composition according to the present invention is alsouseful for producing such foams. The foaming agent is added inconcentrations preferably between 0.1% to 0.2% by weight based on theweight of the composition.

The composition of this invention can be processed in conventionalmanner using, for example, conventional machinery useful for compressionmolding, injection molding, blow molding, extrusion and coextrusion(rod, pipe and film extrusion), or vacuum molding to produce knownarticles. The articles include for example advertising (throw away)articles, labels, cups, flower pots, thread spools, candle cups, holdingdevices, bottles, table-ware, cutlery, and similar articles, packagingmaterials like sheets, films, laminated films sacks, bags, foams, pipes,rods, granules or powders. The following examples illustrate theinvention.

EXAMPLE 1

a) 5 parts of commercial gelatine (100 bloom, isoelectric point at p_(H)4.9) are given into a mixer together with 35 parts of water. To theaqueous gelatine obtained are added 60 parts or organosolv lignin and 5parts of glycerin. The mixture is heated to 65° C. under stirring,cooled, dried to a water content of 18%, and granulated. The granulatewas given into a heated press and kept for 10 minutes under pressure andat 150° C. A stable shaped article was obtained with good properties.

b) 5 parts of commercial gelatine (100 bloom, isoelectric point at p_(H)4.9) are given into a mixer together with 35 parts water. The mixtureobtained is equilibrated to an acid value (p_(H)) of 11.5 by theaddition of sodium hydroxide, 60 parts of organosolv lignin and 5 partsof glycerin are added. The mixture is heated to 65° C. while stirringand then treated as described in part a) of Example 1. Shaped articleswith good properties are obtained.

EXAMPLE 2

a) 18 parts of commercial gelatine (150 bloom, isoelectric point atp_(H) 4.9) are given into a mixer together with 200 parts of water. 42parts of organosolv lignin are added. Then, 8 parts glycerin and 80parts of sawdust are added under stirring and left for one hour. Theproduct is isolated and left drying over night to a water content of 18%The powder obtained is given into a heated press and kept for 10 minutesunder pressure and at a temperature of 160° C. A stable shaped articlewas obtained with good properties.

b) 18 parts of commercial gelatine (150 bloom, isoelectric point atp_(H) 4.9) are given into a mixer together with 200 parts of water. Themixture obtained is equilibrated to an acid value (p_(H)) of 11.5 by theaddition of sodium hydroxide. 42 parts of organosolv lignin. Then 8parts of glycerin and 80 parts of sawdust are added. The mixture isfurther treated as described in part a) of this Example 2.

c) Example 2a and Example 2b) are repeated with the difference thatafter the addition or organosolv lignin the acid value is againequilibrated to an acid value (p_(H)) of 11.5. The mixture is thenstirred for 1 hour and 8 parts of sawdust are added. In the examples2a), 2b) and 2c) there are obtained stable shaped articles with verygood properties.

EXAMPLE 3

a) 18 parts of commercial gelatine (150 bloom, isoelectric point atp_(H) 4.9) are given into a mixer together with 300 parts of water. 40parts of organosolv lignin, 8 parts of glycerin and 60 parts of sawdustare added under stirring. The mixture is spray-dried whereby a granulateis obtained having a water content of 16%. The granulate may be formedin a heated press to stable shaped articles of various densities wherebythe material is treated for 1 minute to 10 minutes at temperatures from110° C. to 160° C. at pressures of from 1.1 bar to 10 bars.

b) 18 parts of commercial gelatine (150 bloom, isoelectric point atp_(H) 4.9) are given into a mixer together with 300 parts of water. Themixture obtained is equilibrated to an acid value (p_(H)) of 11.5 by theaddition of sodium hydroxide. 40 parts of organosolv lignin, 8 parts ofglycerin and 60 parts of sawdust are added and spray dried to agranulate having a water content of 16%. The mixture is further treatedas described in part a) of this Example 3.

EXAMPLE 4

To 50 parts of product obtained according to the Example 1a), 1b), 2a),2b), 2c), 3a) and 3b) are added each time 12.5 parts or pre-plasticisedpolyvinyl alcohol (Example 4a) with an average molecular weight of60′000 and a degree of hydrolysis of about 87-89 mol % and (Example 4b)with an average molecular weight of 108′000 and a degree of hydrolysisof about 98-99 mol %, and each time 5 parts of glycerin. The mixture iswell mixed. The water content is 20% by weight calculated to the totalweight of the mixture. The mixture is heated in a press for 5 minutes to150° C. and in a further test for 10 minutes to 130° C. each time at 1.5bar, 5 bar and 20 bar. Test-pieces are obtained with very goodproperties. In this way various shapes like spools, labels, packagingmaterials with low densities for examples for ampoules, may be produced.

EXAMPLE 5

100 parts of the granulate obtained according to Examples 1a), 1b), 2a),2b), 2c), 3a) and 3b) are mixed in a mixer with (a) 85 partspoly-epsilon-caprolactone and (b) 120 parts poly-epsilon-caprolactoneand 50 parts polyvinyl alcohol (degree of hydrolysis 88%, averagemolecular weight about 80′000), 50 parts ethylene-vinylalcohol-copolymer(with about 44 mol % ethylene content), 15 parts polyethylene glycol(average molecular weight: 15′000) and 5 parts sodium stearate. Themixture is treated in an extruder to form a granulate. The temperatureof the melt in the extruder is kept at 165° C. The granulate with lessthan 9% may be processed into films or may be vacuum formed or shapedinto other shaped articles.

EXAMPLE 6

The following compositions are treated analogous to Example 5 andprocessed into shaped articles.

TABLE 1 Example No. lignin/gelatine PCL PVOH polymer 6a 30.5% 30.5% 10%EVOH, 10% 6b 39.5% 34.5% 10% EVOH, 5% 6c 30.5%   30% — polyester- amide,20% 6d   15%   15% 17% EVOH, 30% 6e   30%   50% — polyethylene, 4% 6f  50% 25.5% — EVOH, 6.5% EAA, 5% lignin/gelatine-reaction product, 25%gelatine (Example 6a, 6b); 40% gelatine (Example 6c, 6d); 50% gelatine(Example 6e); 60% gelatine (Example 6f), calculated to the dry substancePCL = polycaprolactone (poly-epsilon-caprolactone) EAA =ethylene/acrylic acid-copolymer, acrylic acid content: 10 mol % PVOH =polyvinyl alcohol, molecular weight (MW) (i) ca. 90,000, 87 mol % degreeof hydrolysis (DH) und (ii) MW ca. 108,000 DH 98-99 Mol % EVOH =ethylene/vinyl alcohol-copolymer, ethylene content: 28 mol % totalcomposition = 100% water: 4.5% (calculated to lignin/gelatine) rest:lubricant and plasticiser (lecithin 0.5%; und Na-stearate, polyethyleneglycol, glycerine) polyesteramide = polyesteramide-copolymer

EXAMPLE 7

The following compositions are prepared an processed analogous toExample 5

TABLE 2 deprot. Example no. gelatine lignin/sawdust PVOH polymer 7a 5.5%15.5%/70%   — — 7b   4% 18%/69% — — 7c  15%  0%/72% — — 7d  20%  0%/52%18% — 7e  15% 15%/58% — — 7f   5% 12%/62%  8% EVOH, 3.5% 7g 8.5%25.5%/34%    6% PCL, 16% 7h 2.5% 2.5%/68%  — EAA, 3% 7i  20%   30%/20.5%14% EVOH, 5% deprot. gelatine = deprotonated gelatine lignin: as drysubstance, organosolv or Kraft-lignin PCL = polycaprolactone(poly-epsilon caprolactone) EAA = ethylene/acrylic acid-copolymer,acrylic acid content: 10 mol % EVOH = ethylene/vinyl alcohol-copolymer,ethylene content: 28 mol %, total composition = 100% water: 22.5% rest:lubricant and plasticiser (lecithin 0.5%, und Na-stearate)

EXAMPLE 8

To the compositions according to Examples 6 and 7, as given in theTables 1 and 2, are added further components such as syntheticthermoplastic polymers and copolymers, such as polyethylene, polyvinylacetate, polyester, polyamide, ethylene/acrylic acid copolymers,ethylene/maleic-anhydride-copolymers, poly-beta-hydroxy-butyrate,poly-gamma-hydroxy-butyric acid, poly-gamma-valerolactone, each time inquantities of 5%, 10%, 15%, 20%, 30% or 40% (each time in weight percentcalculated to the weight of all the components present).

What is claimed is:
 1. A biodegradable composition, wherein saidcomposition has been obtained by heating and melting together at leastone lignin or a lignin containing material with a protein, and saidcomposition contains one or more additives, whereby said additives areselected from the group consisting of modifying agents, alkenolpolymers, fillers, lubricants, plasticizers, stabilizers, flameretardants, dyestuffs, nucleating agents, foaming agents, pigments andmixtures thereof, said lignin or lignin derivative reacted with saidprotein such that said composition contains at least one syntheticthermoplastic polymer selected from the group consisting ofpolyolefines; poly(vinyl acetates) and partially hydrolyzedpolyvinylacetate with a degree of hydrolysis of 10 mol % to 50 mol %′polystyrene; poly(acrylic acid) esters or poly(methacrylic acid) esters;thermoplastic polycondensates; alkylene/acrylic acid copolymers oralkkylene/methacrylic acid copolymers, alkylene/maleic anhydridecopolymers; and alkylene/vinylacohol copolymers.
 2. A compositionaccording to claim 1, wherein the weight ratio of the dry lignin or thedry lignin containing material to the dry protein in said composition isfrom about 99.95:0.05 to about 20:80.
 3. The composition of claim 2,wherein the ratio is from about 99.95:0.05 to about 40:60.
 4. Thecomposition of claim 3, wherein the ratio is from about 98:2 to about60:40.
 5. The composition of claim 4, wherein the ratio is from about97:3 to about 75:25.
 6. A composition according to claim 2, wherein saidcomposition is present in the form of a powdery mixture, a spray driedpowder, a melt or a shaped article made thereof.
 7. A compositionaccording to claim 4, wherein the lignin is made from a wood selectedfrom fir-wood, spruce, oak-tree, aspen, pine-tree and straw and ispresent in the form of sulfate-lignin, sulphonate-lignin,organosolv-lignin, lignin which has been treated under vapour pressureand acid-treated lignin.
 8. A composition according to claim 7, whereinthe lignin containing material is a wood in the form of small or fineparticles.
 9. A composition according to claim 7, wherein the lignin isa chemically modified lignin.
 10. A composition according to claim 1,wherein the protein is a vegetable or a animal gelatine or casein or achemically modified protein.
 11. A composition according to claim 10,wherein the protein is a deprotonated protein, which been deprotonatedat least about pH
 8. 12. The composition of claim 11, wherein the pH isat least about pH
 10. 13. The composition of claim 12, wherein the pH isat least about ph 11.5.
 14. A composition according to claim 1, whereinsaid composition contains a synthetic biodegradable polymer.
 15. Acomposition according to claim 1, wherein composition contains starchand/or chemically modified starch.
 16. A composition according to claim1, wherein said composition has been formed to shaped articles using amethod selected from compression molding, injection molding, blowmolding, extrusion or co-extrusion (rod-tube-and film-extrusion) vacuummolding.
 17. A composition according to claim 16, wherein said shapedarticle is present in the form of an advertising article, label, cup,flower pot, spool, candle-cup, holding device, table-ware, cutlery,bottles, packaging materials, films, laminated films, sacks, bags,foams, tubes, rods, granulates or powders.
 18. A composition accordingto claim 1, which is derived from a starting composition containingcomponents selected from: (i) a lignin or a lignin containing material;(ii) a protein which has been deprotonated and (iii) one or moreadditives which are selected from the group comprising modifying agents,alkenol polymers, fillers, lubricant, plasticisers, thermoplasticpolymers, stabilizers, flame retardants, dyestuffs, nucleating agents,foaming agents, pigments and mixtures thereof, wherein the weight ratioof the dry lignin and/or the dry lignin containing material to the dryprotein in said composition is from about 99.95:0.05 to about 20:80. 19.A composition according to claim 1, wherein said synthetic thermoplasticpolycondensate further comprises a thermoplastic polyester, athermoplastic polyamide, a thermoplastic polyester amide or athermoplastic poly(amide anhydride).
 20. A composition according toclaim 19, wherein the synthetic thermoplastic polycondensate furthercomprises a biodegradable polyester, a biodegradable polyamide, abiodegradable polyester amide or a biodegradable poly(amide anhydride).21. A composition according to claim 20, wherein said biodegradablepolyester is derived from aliphatic hydroxy-carbonic acids with 1 to 24carbon atoms made from the corresponding hydroxy-carbonic acids or thecorresponding lactones or lactides.
 22. A composition according to claim20, wherein said biodegradable polyester is derived from lactic acid orthe corresponding lactide; beta-hydroxy-propionic acid,beta-propiolactone or beta-hydroxy-buryric acid, gamma-hydroxy-buryricacid, from gamma-butyrolactone or from gamma-valerolactone;6-hydroxy-carbonic acid resp. epsilon-caprolactone.
 23. A compositionaccording to claim 20, wherein the biodegradable polyester is derivedfrom lactic acid; gamma-hydroxy-butyric acid, gamma-valerolactone and/or6-hydroxy-carbonic acid or epsilon-caprolactone.
 24. A compositionaccording to claim 20, wherein the biodegradable polyester furthercomprises poly(epsilon-caprolactone).
 25. A composition according toclaim 20, wherein said composition contains an ethylene/vinyl alcoholcopolymer with a molar vinyl alcohol content of at least 50 mol %.